Induction-motor.



H. G. HEIST 6L H. MAXWELL.

INDUCTION MOTOR. APPLICATION HLED MAR. 3l. 1915.

Im/entors: Henry @.Reist, -low/wol Maxwe 'g Their Attorneg UNITED sTATEs PATENT oEEIcE.

HENRY G. EEI'sT AND HOWARD MAXWELL, or` scHENEcTADY, NEW YORK,` AssIGNons TO GENERAL ELECTRIC COMPANY, A CORPORATION 0F NEW YORK.

I INDUCTION-Moron.

' netic cores of'such motors.

It has forits object a simple method of manufacture, which requires avery simple mold. 5

To this end, our invention consists in pouring molten metal into a mold surrounding the magneticy core of an induction motor and simultaneously rotating the mold and core at suiiicient speed to drive the molten `.metal into the conductor receiving openings in theI core by centrifugal force, and continuing the rotation until the poured metal has congealed. In this way, the molten metal is caused to flow Very quickly through the openings in the core before it chills, and it also forces any air out of the openings in the core which tends to be trapped therein. The

mold is preferably formed with recesses for forming end or short-circuiting rings for the conductor bars. In carrying out our method, inner cores for the end rings are dispensed with, which allows the end rings to shrink uniformly upon cooling and thus prevents theml from cracking. l

Our invention also consists in a mold for carrying 'out this method.

For a better understanding of our invention,l reference may be had to the following description taken in connection with the accompanying drawing, in which- Figure 1 is a view partly in section of a mold and core embodying our invention and by means of which our new-method has been carried out; Fig. 2is a section on the line '2 2 of Fig. 1; Fig. 3 is a sectional view of a squirrel cage cast in position on the secondary core of an induction motor; and Fig. 4 is a fragmentary view, similar to Fig. 1, of a modification. n y

Referringto the drawing, 1 is a secondary magnetic core member of an induction motor, the outer periphery y of which is cylindrical. This core member is provided with Specication of Letters Patent.

Application led March 31, 1915. Serial No. 18,256.

substantially longitudinally extending, conductor receiving openings therethrough. Theseopenings may be either open or closed slots. In Figs. 1 to 3 they are shown as open, that is, with a small opening extendlng` from the slot to the periphery of the core member. The laminations forming the core member 1 may be clamped together between plates 15- by means of bolts 16. The mold for the squirrel cage comprises cylindrical portions extending beyondthe ends of the core and end flange portions 3 and 4. The cylindricalportions in Figs. 1 and 2 are shown as comprised in a member 5, which preferably embraces the outer periph-l ery of the core member 1 and is shown as being divided along linesy substantially parallel to the axis ofthe core member into a plurality of parts 5. The parts 5 of the member 5 may fit in grooves in the flange portions and 4, bolts 6 being provided for clamping the portions of the mold in place, that is, the flange portions to the member 1. The end flange portion 3 has an opening 7 through which molten metal is received, the molten metal being caused to flow by centrifugal force through the conductor receiving openings in the core member 1 to forman end ring 8 between the flange portion 4, the member 5` and the end of the core, conductors9 in the openings in the core member 1, and an end ring 10 between the flange portion 3, member 5, and the core member 1.

The mold'and the core member 1 are rotated asia unit in any suitable manner. We have shown for this purpose a mandrel 11 fastened in the shaft receiving opening 12 in the core member, the mandrel 11 having mounted thereon a belt pulley 13, the whole being rotated by means of a belt 14. While laminations forming the core member 1 together until the squirrel cage is cast vin place. As the laminations forming the core member become hot near their periphery due to the heat absorbed from the molten metal, their outer portions are liable to expand and buckle unless .some provision is made for allowing the portions of the laminations near the shaft receiving opening 12 to expand. In Fig. 2, We have shown the laminations slit from the Ventilating ducts 19 to the shaft receiving opening along lines jso 18 for this purpose. Fig. 3 shows a core member with the squirrel cage cast in place, and the mold, mandrel, clamping plates,` 15 and bolts 16 removed. An ordinaryshaft is then driven into the shaft receiving opening 12 and permanent clamping plates for clamping the lam-in'ations together are placed in position and. held in place by means of bolts or rivets extending through holes 17.

core'member 1 is provided withclosed slots. The mold for casting the squirrel cage in this case comprises cylindrical portions 2 extending beyond the ends of the core member 1 and end flange portions 3. Such cylindrical end lflange portions are provided at each end of the core member, but those at the up'per end only are shown. The end flange portion 3 -is provided with an opening 7 through which molten metal is received for forming the cast parts Pof the squirrel cage.

- clamped in place b means of bolts 6. A

casting is made in t e same Way as that described in connection with Figs. l and 3.

We prefer to use aluminum for this cast'- ing as it may be molded at a low temperature and is llight in Weight, but any other suitable metal, such as copper, may be used.

We desire it to be understood that our invention is not limited to the-particular arrangement shown and described, and We aim in the appended claims to cover all modifi- .cations which do not depart from the spirit and scope of our invention. v

What we claim as new and desire to secure by Letters Patent of the United States, is

1. The process of forming an inductionl motor squirrel cage on a magnetic core having substantially longitudinally extending, conductor receiving openings therethrough which consists in pouring molten metal into 'a mold surrounding the core and simultaneously rotating said mold and core at sufficient speed to drive the molten metal into the conductor receiving openings by centrifugal force, and continuing such rotation until the poured metal has congealed.

2. The process of forming an induction motor squirrel cage on a magnetic core having substantially longitudinally extending,

- conductor receiving openings therethrough which consists in pouring molten metal-into a mold surrounding the core and simultane- The portions of the mold are ousl'y rotating said mold, and core at sufi`1' cient speed to drivethe molten metal into the conductor receiving openings and into the end ring recesses in said mold by centrifugal force, and continuing such rotation until the poured'metal'has congealed.

3. In combination with a cylindrical magnetic core member of an induction motorl tending beyond the ends of the core, and

means for rotating said core and mold.

A 4. In combination with a .cylmd'rical magnetic core member of an induction motor `provided with substantially longitudinally extending, conductor receiving lopenings therethrough, of a mold comprlsmg end flange portions and cylindrical portions ex- In the modifications shown in Fig. 4 the said core and mold.

5.'In, combination with a cylindrical magnetic-core member of an induction motor provided with substantially longitudinally extending, conductor receiving openings therethrough, of a 'mold comprising end flange portions, cylindrical portions extending beyond the ends of the core, and means for clampin said end flange ortions and said cylindrical portions in piace, one of said end flange-portions being provided with an opening through which molten metal is received for forming conductors in the conductor receiving openings in said core and rings for short-circuit the conductors at the ends lof the core, an means for rotating said core and mold.

"6. The combination. with a cylindrical, magnetic core member of an induction -motor provided with substantially longitudinally extending, conductor receiving openings therethrough, of a mold comprising end lia-nge portions and a member embracing the outer periphery of said core and extending beyond t e 'ends of the core, and means for rotating said core and mold.

7. The combination with -a cylindrical,

magnetic core member of an induction mo-.- 'tor prov1ded with substantially longitudivnally extending, conductor `receiving openrings for short-circuiting the conductors at the ends of the core, 'and means for rotating said core and mold. v

8. The .combination with a cylindrical, magnetic core member of an induction monally extending, conductor receiving openings therethrough, of a mold comprising a member embracing the outer periphery of said core and extending beyond' the ends of the core, end flange portions, and means for clamping said ianges to said member,.and means for rotating said core and mold.

9. The combination with a cylindrical, magnetic core member of an induction motor provided with, substantially longitudinally extending, conductor receiving openi y ings therethrough, of a mold comprising a provided' with 'an openin molten metal 1s received' or forming con.

member embracmg the outer periphery of said core and extending beyond the ends of the core, end flange portions, and means :for clamping said flange portions to said member, one of said ange portions being through which ductors in the conductor receiving openings 1n sald core and rings for Short-01r- .cuiting said conductors at the ends of said core, and means for rotating said core and -mo1d. f

10. The' combination with a cylindrical, magnetic core member ofan induction motor provided with substantially vlongitudinally extending, conductor receiving openings therethrough, of a mold vcomprising a member divided along lines substantially parallel to the axis of said core member into a pluralityof parts, said parts .em-

` bracing the outer periphery of saidcore tor provided with substantially longitudiand extending beyond thefends of the core, end iange portions, and means for clamping said ange portions to said. member, and means for rotating said core and said mold..

11. The combination with a cylindrical, magnetic core member of an induction mo- -tor providedwith substantially longitudinally extending, conductor receiving openings therethrough, of a mold comprising a member divided along lines substantially parallel to the axis of said core member into a plurality of parts,` said parts embracing the` outer peri hery of said core and extending beyond t e ends of the core,

end flange portions, and means for clamp-vv A'ing said ange portions to said member, one of said flange portions being provided with an opening through which molten metalis received for forming conductors in the conductor receiving openings in said core and rings for short-clrcuiting the conductors at the ends of the core, and means vfor rotating said core and mold.

In vvitnessfwhereof, vve-have hereunto set our hands Ithis 29th day of March 1915.

HENRY G. REIST. HOWARD MAXWELL. 

